diff --git a/Tests/HtmlSanitizerAllTest.php b/Tests/HtmlSanitizerAllTest.php
index 18c175b..bdb47d7 100644
--- a/Tests/HtmlSanitizerAllTest.php
+++ b/Tests/HtmlSanitizerAllTest.php
@@ -38,7 +38,7 @@ public function testSanitizeHead(string $input, string $expected)
         $this->assertSame($expected, $this->createSanitizer()->sanitizeFor('head', $input));
     }
 
-    public function provideSanitizeHead()
+    public static function provideSanitizeHead()
     {
         $cases = [
             // Scripts
@@ -71,7 +71,7 @@ public function testSanitizeBody(string $input, string $expected)
         $this->assertSame($expected, $this->createSanitizer()->sanitize($input));
     }
 
-    public function provideSanitizeBody()
+    public static function provideSanitizeBody()
     {
         $cases = [
             // Text
diff --git a/Tests/TextSanitizer/StringSanitizerTest.php b/Tests/TextSanitizer/StringSanitizerTest.php
index a8149f2..52d992d 100644
--- a/Tests/TextSanitizer/StringSanitizerTest.php
+++ b/Tests/TextSanitizer/StringSanitizerTest.php
@@ -16,7 +16,7 @@
 
 class StringSanitizerTest extends TestCase
 {
-    public function provideHtmlLower()
+    public static function provideHtmlLower()
     {
         $cases = [
             'exampleAttr' => 'exampleattr',
@@ -38,7 +38,7 @@ public function testHtmlLower(string $input, string $expected)
         $this->assertSame($expected, StringSanitizer::htmlLower($input));
     }
 
-    public function provideEncodeHtmlEntites()
+    public static function provideEncodeHtmlEntites()
     {
         $cases = [
             '' => '',
diff --git a/Tests/TextSanitizer/UrlSanitizerTest.php b/Tests/TextSanitizer/UrlSanitizerTest.php
index 18fec32..dd19a1d 100644
--- a/Tests/TextSanitizer/UrlSanitizerTest.php
+++ b/Tests/TextSanitizer/UrlSanitizerTest.php
@@ -24,7 +24,7 @@ public function testSanitize(?string $input, ?array $allowedSchemes, ?array $all
         $this->assertSame($expected, UrlSanitizer::sanitize($input, $allowedSchemes, $forceHttps, $allowedHosts, $allowRelative));
     }
 
-    public function provideSanitize()
+    public static function provideSanitize()
     {
         // Simple accepted cases
         yield [
@@ -312,7 +312,7 @@ public function testParse(string $url, ?array $expected)
         }
     }
 
-    public function provideParse(): iterable
+    public static function provideParse(): iterable
     {
         $urls = [
             '' => null,